Covariance and coherence matching for binaural room impulse responses; implementation and evaluation of rendering methods using different-order ambisonics
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Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Sound and vibration (MPSOV), MSc
Publicerad
2022
Författare
Hedlund , Elin
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Rendering binaural room impulse responses with the use of spherical microphone
arrays and sets of head-related transfer functions minimize required measurements
but will however exhibit a difference in perception due to, among other things,
spherical harmonic truncation. By utilizing the spatial perceptually relevant interaural
cues, the similarity to a directly measured BRIR could be enhanced.
In this thesis, two different methods for rendering binaural room impulse responses
with different-order Ambisonics are employed to evaluate and compare the
similarity between the generated BRIRs and directly measured counterparts using
an artificial head and torso recording. Both methods utilize inter-aural cues within
the inter-aural coherence and covariance matrix, respectively, in order to process
the diffuse part of the BRIR.
The results show an improvement for the covariance matrix framework compared
to the coherence matching method, even for rendering employing first-order Ambisonics.
A pilot study in the form of an informal listening test was conducted to
investigate the perceived similarity between the generated and measured BRIRs.
The results of the listening test indicate that an increased spatial resolution due to
higher-order Ambisonics will enhance the perceived similarity, while also displaying
varying results depending on rendering method. However, a more extensive listening
test would be beneficial. The findings indicate that the covariance framework
with even higher-order Ambisonics would further optimize the quality and perceived
similarity.
Beskrivning
Ämne/nyckelord
Ambisonics, Binaural Rendering, Covariance, Coherence, Spherical Harmonics